Invermere
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Invermere clear sky chart from 2005-11-06 to 2026-07-01.

This page is a summary of past forecasts. Even though it's based only on forecasts, some people use these pages as clue to a site's climate. But climate data based on actual observation should be preferred (if you can find it!).

Cloud, Transparency and Seeing forecasts are summarized individually. But because good observing conditions require a combination of minimum cloud cover, transparency and seeing, the individual forecast summaries can be difficult to interpret. The observing conditions section counts the combinations of conditions needed for common types of astronomical observation.

Observing Conditions

The following tables count the occurrence of the combinations of forecast and darkness conditions needed for different observations. Conditions are rated by by what percentage of the hours the observation would likely be attempted are usable.

Observation Type	Minimum conditions for hour to be usable				Out of hours
	Clear of Clouds	Transparency	Seeing	Sky Brightness
Planetary:	50%	(no limit)	Average	(no limit)	Nighttime Hours
Deep Sky:	70%	Average	(no limit)	5.9	Nighttime Hours
CCD Imaging:	70%	Below Average	Poor	(no limit)	Nighttime Hours

Percentages are of nighttime hours per month, or per year, when a particular observing conditions was met. Deep Sky percentages never exceed 50% because the moon is up half the time. Deep sky percentages are much lower for charts at high latitudes because of fewer dark hours in the summer.

Overall

By Month

Individual Forecasts

The length of each colored bar in the "occurrence of each Forecast" column is proportional to the number of times the chart forecast that color. The percentages are of the total number of hours per month, or per year, with a particular forecast. The colors as the same as those used in clear sky charts.

Note: Transparency probabilities are only counted for those hours that have 30% or less cloud cover. Seeing probabilities are only counted for those hours that have 80% or less cloud cover. If that's too tricky, try Observing Conditions instead.

Overall

		Occurrence of each Forecast	Data Points
Cloud Cover	Day	4 7% 3 8% 6% 6% 6% 5% 8% 9% 37%	142073
	Night	3 7% 4 10% 6% 6% 6% 5% 7% 9% 35%	138975
Transparency	Day	37% 16% 21% 19% 7% 1	141790
	Night	38% 17% 21% 17% 6% 1	138841
Seeing	Day	10% 17% 34% 27% 11% 2	17301
	Night	6% 9% 42% 32% 10% 1	26342

By Month

Percentage Cloud Cover NW (2006-)
Color Meanings: Overcast 90% covered 80% covered 70% covered 60% covered 50% covered 40% covered 30% covered 20% covered 10% covered Clear
Month	Days in Month		Occurrence of each Forecast	Data Points
January	1st to 10th	Day	1 7% 5% 17% 10% 9% 9% 7% 10% 9% 16%	4125
	11th to 20th	Day	1 5% 3 10% 8% 7% 6% 5% 7% 10% 40%	4629
	21st to end	Day	1 8% 6% 14% 7% 7% 6% 5% 8% 8% 28%	5186
February	1st to 10th	Day	1 7% 4 11% 9% 8% 8% 7% 11% 10% 24%	1680
	11th to 20th	Day	1 7% 5% 10% 8% 8% 8% 6% 11% 11% 27%	1822
	21st to end	Day	1 8% 3 10% 10% 9% 8% 7% 9% 9% 26%	1730
March	1st to 10th	Day	1 6% 4 9% 5% 5% 7% 6% 9% 11% 36%	4618
	11th to 20th	Day	1 5% 3 8% 6% 7% 8% 6% 9% 11% 35%	4884
	21st to end	Day	2 9% 4 9% 7% 7% 8% 8% 9% 10% 27%	5912
April	1st to 10th	Day	5% 11% 4 9% 7% 6% 6% 5% 9% 9% 29%	2520
	11th to 20th	Day	5% 11% 4 10% 6% 6% 6% 5% 8% 10% 30%	2668
	21st to end	Day	6% 10% 4 10% 7% 7% 6% 5% 8% 8% 29%	2730
May	1st to 10th	Day	6% 8% 3 5% 4 4 5% 4 7% 9% 44%	8134
	11th to 20th	Day	6% 9% 4 10% 7% 7% 7% 6% 8% 9% 26%	8489
	21st to end	Day	9% 7% 2 8% 5% 5% 6% 5% 7% 10% 36%	9649
June	1st to 10th	Day	13% 10% 4 8% 6% 5% 5% 5% 6% 7% 32%	3150
	11th to 20th	Day	12% 9% 3 9% 6% 6% 6% 5% 7% 8% 31%	3150
	21st to end	Day	8% 5% 2 6% 5% 5% 7% 6% 8% 8% 39%	3150
July	1st to 10th	Day	4 3 2 5% 3 4 4 4 6% 8% 57%	6781
	11th to 20th	Day	5% 3 2 4 3 4 5% 4 7% 9% 55%	6743
	21st to end	Day	3 3 1 4 4 4 5% 5% 7% 10% 52%	6874
August	1st to 10th	Day	4 3 2 6% 4 4 6% 5% 8% 9% 49%	4541
	11th to 20th	Day	5% 4 2 5% 4 4 6% 5% 8% 10% 47%	4313
	21st to end	Day	5% 4 2 4 4 5% 5% 4 7% 9% 52%	4618
September	1st to 10th	Day	5% 6% 2 5% 4 4 5% 5% 6% 9% 49%	2400
	11th to 20th	Day	7% 6% 2 6% 5% 5% 6% 5% 6% 9% 44%	2253
	21st to end	Day	7% 6% 3 8% 5% 5% 5% 6% 7% 9% 40%	2200
October	1st to 10th	Day	3 5% 2 5% 4 4 5% 5% 7% 10% 49%	3502
	11th to 20th	Day	2 4 2 6% 4 5% 6% 5% 9% 13% 44%	2932
	21st to end	Day	3 8% 3 8% 6% 7% 6% 5% 7% 10% 38%	3200
November	1st to 10th	Day	3 9% 6% 12% 8% 8% 7% 7% 8% 9% 24%	1851
	11th to 20th	Day	2 7% 5% 13% 9% 9% 8% 7% 9% 9% 24%	1522
	21st to end	Day	1 6% 4 14% 11% 9% 7% 7% 11% 11% 18%	1470
December	1st to 10th	Day	2 5% 2 13% 11% 10% 9% 8% 10% 10% 22%	2360
	11th to 20th	Day	1 9% 6% 20% 11% 9% 7% 5% 8% 8% 16%	2712
	21st to end	Day	1 9% 7% 18% 9% 9% 9% 6% 8% 8% 17%	3575
January	1st to 10th	Night	1 9% 6% 20% 10% 9% 9% 6% 7% 8% 16%	8768
	11th to 20th	Night	5% 3 10% 7% 7% 8% 7% 10% 11% 32%	8325
	21st to end	Night	2 12% 7% 14% 7% 6% 7% 6% 7% 9% 25%	8994
February	1st to 10th	Night	1 11% 5% 14% 9% 9% 8% 6% 9% 9% 19%	2940
	11th to 20th	Night	1 10% 6% 11% 8% 7% 7% 6% 8% 9% 27%	2680
	21st to end	Night	1 8% 3 12% 9% 8% 7% 6% 8% 9% 29%	2076
March	1st to 10th	Night	1 6% 3 9% 6% 5% 6% 6% 8% 10% 40%	5496
	11th to 20th	Night	1 6% 2 7% 6% 6% 7% 7% 10% 11% 36%	5335
	21st to end	Night	3 11% 4 9% 5% 6% 7% 6% 9% 11% 30%	5301
April	1st to 10th	Night	3 11% 3 6% 5% 5% 5% 5% 7% 10% 40%	2100
	11th to 20th	Night	3 10% 3 8% 5% 5% 5% 6% 8% 9% 38%	1902
	21st to end	Night	4 9% 3 7% 5% 5% 6% 5% 6% 10% 40%	1890
May	1st to 10th	Night	6% 8% 3 6% 4 3 4 3 5% 7% 52%	4784
	11th to 20th	Night	7% 9% 3 9% 5% 5% 5% 5% 7% 10% 34%	4368
	21st to end	Night	7% 7% 2 5% 5% 5% 6% 5% 7% 9% 42%	4522
June	1st to 10th	Night	12% 6% 3 6% 4 5% 5% 4 6% 10% 39%	1470
	11th to 20th	Night	10% 8% 2 7% 5% 5% 5% 6% 8% 8% 37%	1470
	21st to end	Night	6% 4 1 6% 4 4 4 5% 7% 10% 49%	1470
July	1st to 10th	Night	3 4 1 5% 3 4 4 3 5% 7% 60%	3180
	11th to 20th	Night	5% 3 1 4 3 3 4 3 6% 10% 57%	3214
	21st to end	Night	4 2 1 3 2 3 3 3 5% 9% 63%	3969
August	1st to 10th	Night	4 4 1 5% 3 4 5% 5% 7% 10% 50%	2609
	11th to 20th	Night	5% 4 2 5% 4 4 5% 4 6% 10% 52%	2739
	21st to end	Night	5% 5% 2 5% 3 3 4 3 6% 8% 56%	3278
September	1st to 10th	Night	6% 3 1 4 3 3 4 4 7% 9% 56%	2000
	11th to 20th	Night	7% 6% 2 6% 3 4 4 4 6% 8% 51%	2146
	21st to end	Night	6% 5% 2 4 3 5% 4 5% 7% 9% 50%	2200
October	1st to 10th	Night	3 4 2 5% 4 3 4 4 7% 11% 53%	3681
	11th to 20th	Night	3 5% 1 6% 4 4 6% 6% 7% 10% 50%	4216
	21st to end	Night	3 6% 3 9% 6% 6% 6% 6% 8% 11% 37%	4600
November	1st to 10th	Night	5% 11% 5% 10% 6% 6% 6% 7% 9% 9% 25%	2665
	11th to 20th	Night	3 10% 5% 12% 10% 7% 7% 5% 8% 10% 23%	3074
	21st to end	Night	2 10% 5% 17% 10% 8% 8% 5% 8% 9% 18%	3150
December	1st to 10th	Night	2 7% 3 16% 11% 10% 9% 6% 8% 10% 19%	5040
	11th to 20th	Night	1 8% 5% 22% 12% 10% 8% 6% 7% 7% 14%	5700
	21st to end	Night	2 11% 9% 23% 10% 9% 6% 4 6% 6% 13%	7623

Transparency (when cloud cover <= 30%)
Color Meanings: Too cloudy to forecast Poor Below Average Average Above average Transparent
Month	Days in Month		Occurrence of each Forecast	Data Points
January	1st to 10th	Day	46% 24% 18% 9% 2	4125
	11th to 20th	Day	33% 20% 20% 19% 6% 2	4653
	21st to end	Day	38% 23% 24% 13% 2	5187
February	1st to 10th	Day	50% 18% 16% 10% 7% 1	1680
	11th to 20th	Day	46% 19% 18% 12% 4	1830
	21st to end	Day	48% 18% 18% 12% 5%	1730
March	1st to 10th	Day	37% 18% 21% 17% 7%	4618
	11th to 20th	Day	32% 16% 27% 20% 5%	4885
	21st to end	Day	43% 22% 20% 11% 4	5912
April	1st to 10th	Day	49% 16% 22% 10% 2	2520
	11th to 20th	Day	48% 15% 21% 14% 2	2668
	21st to end	Day	50% 14% 18% 15% 3	2730
May	1st to 10th	Day	33% 11% 23% 25% 7%	8134
	11th to 20th	Day	42% 17% 18% 19% 4	8493
	21st to end	Day	36% 15% 25% 20% 3	9650
June	1st to 10th	Day	50% 10% 15% 17% 8% 1	3150
	11th to 20th	Day	48% 13% 16% 17% 6%	3150
	21st to end	Day	38% 15% 18% 18% 10% 1	3150
July	1st to 10th	Day	23% 8% 17% 29% 21% 3	6707
	11th to 20th	Day	23% 10% 20% 25% 18% 4	6662
	21st to end	Day	23% 10% 23% 22% 17% 5%	6681
August	1st to 10th	Day	25% 13% 18% 32% 9% 2	4524
	11th to 20th	Day	27% 14% 25% 25% 8% 1	4355
	21st to end	Day	26% 12% 29% 25% 8% 1	4617
September	1st to 10th	Day	30% 10% 22% 26% 11% 1	2400
	11th to 20th	Day	36% 12% 18% 25% 8% 1	2253
	21st to end	Day	39% 13% 21% 20% 6% 1	2200
October	1st to 10th	Day	27% 14% 33% 22% 3	3502
	11th to 20th	Day	28% 19% 28% 19% 6%	2932
	21st to end	Day	37% 18% 25% 16% 3	3200
November	1st to 10th	Day	56% 17% 14% 11% 2	1851
	11th to 20th	Day	53% 17% 18% 9% 3	1522
	21st to end	Day	50% 20% 19% 8% 3	1470
December	1st to 10th	Day	48% 26% 17% 7% 1	2360
	11th to 20th	Day	55% 23% 14% 7% 2	2714
	21st to end	Day	44% 22% 18% 12% 3	3575
January	1st to 10th	Night	50% 23% 15% 9% 2	8769
	11th to 20th	Night	34% 22% 22% 13% 8% 2	8363
	21st to end	Night	41% 23% 20% 13% 2	8994
February	1st to 10th	Night	56% 15% 14% 10% 5%	2940
	11th to 20th	Night	49% 16% 18% 12% 5%	2682
	21st to end	Night	45% 17% 21% 12% 5% 1	2076
March	1st to 10th	Night	31% 17% 29% 17% 6%	5496
	11th to 20th	Night	29% 18% 28% 21% 4	5335
	21st to end	Night	37% 22% 23% 14% 3	5301
April	1st to 10th	Night	36% 17% 28% 14% 5%	2100
	11th to 20th	Night	39% 13% 24% 18% 5%	1902
	21st to end	Night	38% 12% 22% 22% 5% 1	1890
May	1st to 10th	Night	30% 9% 24% 28% 7% 1	4781
	11th to 20th	Night	37% 15% 22% 24% 3	4368
	21st to end	Night	33% 14% 26% 23% 4	4526
June	1st to 10th	Night	39% 14% 16% 21% 9% 1	1470
	11th to 20th	Night	44% 12% 17% 20% 7%	1470
	21st to end	Night	28% 12% 22% 26% 11% 1	1470
July	1st to 10th	Night	21% 9% 18% 26% 22% 4	3145
	11th to 20th	Night	22% 9% 18% 27% 20% 3	3172
	21st to end	Night	18% 8% 25% 23% 19% 7%	3857
August	1st to 10th	Night	22% 14% 21% 31% 10% 2	2601
	11th to 20th	Night	24% 12% 26% 28% 9% 1	2763
	21st to end	Night	24% 9% 32% 25% 9% 1	3278
September	1st to 10th	Night	23% 13% 22% 28% 14% 1	2000
	11th to 20th	Night	31% 10% 19% 28% 10% 1	2146
	21st to end	Night	28% 12% 26% 24% 9%	2200
October	1st to 10th	Night	23% 15% 29% 29% 5%	3681
	11th to 20th	Night	26% 16% 28% 24% 5%	4216
	21st to end	Night	33% 21% 24% 19% 2	4600
November	1st to 10th	Night	51% 17% 18% 10% 3	2665
	11th to 20th	Night	54% 16% 17% 10% 4	3074
	21st to end	Night	58% 14% 17% 7% 4	3150
December	1st to 10th	Night	49% 25% 17% 8% 1	5040
	11th to 20th	Night	61% 19% 10% 9% 1	5697
	21st to end	Night	55% 19% 16% 8% 2	7623

Seeing (when cloud cover <= 80%)
Color Meanings: Too cloudy to forecast Bad 1/5 Poor 2/5 Average 3/5 Good 4/5 Excellent 5/5
Month	Days in Month		Occurrence of each Forecast	Data Points
January	1st to 10th	Day	5% 12% 35% 31% 10% 6%	220
	11th to 20th	Day	2 9% 38% 37% 11% 3	220
	21st to end	Day	3 10% 40% 35% 9% 3	242
February	1st to 10th	Day	5% 17% 45% 24% 9% 1	220
	11th to 20th	Day	2 11% 40% 36% 9% 1	346
	21st to end	Day	6% 18% 41% 26% 8% 1	446
March	1st to 10th	Day	7% 26% 37% 20% 9% 1	540
	11th to 20th	Day	7% 26% 36% 22% 6% 2	540
	21st to end	Day	9% 21% 37% 22% 9% 1	594
April	1st to 10th	Day	11% 23% 34% 24% 7% 2	540
	11th to 20th	Day	11% 25% 31% 23% 8% 2	532
	21st to end	Day	14% 18% 32% 23% 10% 3	540
May	1st to 10th	Day	13% 21% 32% 23% 8% 2	543
	11th to 20th	Day	16% 16% 28% 26% 12% 2	676
	21st to end	Day	16% 15% 28% 28% 13% 1	844
June	1st to 10th	Day	19% 19% 31% 25% 6%	780
	11th to 20th	Day	15% 21% 32% 22% 9% 1	780
	21st to end	Day	10% 13% 31% 30% 14% 1	780
July	1st to 10th	Day	9% 11% 31% 32% 15% 1	722
	11th to 20th	Day	9% 14% 33% 29% 13% 2	707
	21st to end	Day	5% 14% 34% 31% 13% 3	575
August	1st to 10th	Day	7% 10% 31% 34% 14% 3	527
	11th to 20th	Day	7% 14% 29% 32% 15% 3	517
	21st to end	Day	9% 15% 28% 29% 14% 4	583
September	1st to 10th	Day	10% 18% 26% 25% 14% 7%	530
	11th to 20th	Day	9% 14% 29% 30% 12% 4	530
	21st to end	Day	14% 22% 35% 22% 7% 1	530
October	1st to 10th	Day	13% 13% 34% 28% 10% 2	525
	11th to 20th	Day	7% 18% 40% 23% 10% 2	330
	21st to end	Day	12% 21% 37% 23% 5% 2	363
November	1st to 10th	Day	6% 16% 42% 28% 8%	330
	11th to 20th	Day	7% 17% 50% 16% 8% 2	247
	21st to end	Day	2 15% 42% 29% 8% 5%	220
December	1st to 10th	Day	4 12% 34% 33% 11% 5%	220
	11th to 20th	Day	4 10% 42% 31% 10% 2	220
	21st to end	Day	3 8% 39% 36% 12% 3	242
January	1st to 10th	Night	5% 12% 48% 27% 7% 1	1050
	11th to 20th	Night	3 8% 48% 33% 7% 2	892
	21st to end	Night	3 7% 50% 33% 6% 1	924
February	1st to 10th	Night	4 9% 48% 30% 8% 1	840
	11th to 20th	Night	6% 6% 50% 29% 8% 1	824
	21st to end	Night	3 9% 46% 32% 10%	692
March	1st to 10th	Night	3 10% 53% 24% 9%	840
	11th to 20th	Night	4 12% 49% 26% 8% 1	840
	21st to end	Night	6% 9% 47% 29% 9% 1	924
April	1st to 10th	Night	7% 11% 41% 32% 9%	840
	11th to 20th	Night	7% 11% 44% 31% 6%	654
	21st to end	Night	8% 12% 41% 32% 7%	630
May	1st to 10th	Night	10% 9% 37% 33% 10% 1	441
	11th to 20th	Night	7% 9% 33% 41% 11%	414
	21st to end	Night	15% 5% 30% 39% 11%	455
June	1st to 10th	Night	12% 10% 35% 34% 8%	420
	11th to 20th	Night	12% 9% 37% 32% 10%	420
	21st to end	Night	9% 7% 30% 40% 14%	420
July	1st to 10th	Night	5% 5% 25% 49% 16%	390
	11th to 20th	Night	5% 4 32% 43% 16%	388
	21st to end	Night	2 4 24% 51% 18%	438
August	1st to 10th	Night	5% 3 22% 46% 24% 1	398
	11th to 20th	Night	5% 4 23% 44% 24%	493
	21st to end	Night	6% 9% 25% 40% 20%	680
September	1st to 10th	Night	7% 6% 33% 33% 19% 3	800
	11th to 20th	Night	8% 6% 26% 37% 20% 2	800
	21st to end	Night	10% 8% 37% 34% 10% 1	800
October	1st to 10th	Night	8% 8% 41% 34% 10% 1	800
	11th to 20th	Night	6% 10% 45% 31% 8% 1	800
	21st to end	Night	7% 13% 46% 26% 6% 1	880
November	1st to 10th	Night	9% 12% 48% 24% 6%	820
	11th to 20th	Night	8% 16% 46% 23% 6%	1030
	21st to end	Night	4 10% 48% 28% 8% 1	1050
December	1st to 10th	Night	5% 10% 46% 28% 9% 1	1050
	11th to 20th	Night	4 8% 48% 29% 9%	1050
	21st to end	Night	4 8% 47% 31% 9% 1	1155

Page generated at 2026-06-28 00:10:44. Version ac07

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